Hard Cheese
by librarianmum
Summary: From a challenge by johnsarmylady: how does John react when Sherlock keeps experimenting on his bed?


**Hard Cheese**

**This was written pretty quickly in response to a challenge from the gloriously talented johnsarmylady, whose fics keep me smiling, and quite often guffawing with laughter. It was JAL who had the idea of Sherlock carrying out experiments on John's bed and it was she who challenged me to consider the following scenario. It's not her fault if there are any inaccuracies, either in the text or in the subject matter! I'm no scientist, that's for sure.**

**Oh, and I also borrowed a scenario relating to a certain foodstuff from Jerome K. Jerome's Three Men in a Boat – see if you can guess what!**

**I don't own a thing, sadly. **

* * *

The trouble with 221B Baker Street, Sherlock reflected as he travelled home from Bart's on a chilly November night at 1.30AM, was that it was actually quite small.

Well, in theory, it _wasn't_ small – it was probably perfectly sized for two adults to share, as had been intended – two bedrooms, a bathroom, an open plan living area. Two 'normal' adults, that was.

But, in reality, it _was _too small, because one of those two adults was decidedly _not _normal.

It was certainly _not_ normal of John to react the way he had done to Sherlock's recent experiments. After all, Sherlock had made it clear right from the start – hadn't he? The 'work' came first. And, yes, perhaps it would be useful if Sherlock had a warehouse at his disposal to carry out his experiments, but he didn't, and the laboratory at Bart's could only take him _so_ far…

It was perfectly natural that when a consulting detective investigated domestic murders, it would lead on occasion to his experiments overlapping his home life.

After all, it was vitally important to test the position and spread of brain matter splashed over the walls of the shower, as it would prove beyond doubt that the man's much smaller wife couldn't have committed the crime of bashing her husband's head in with an axe, and that the act was actually carried out by his taller brother. Sherlock was pleased that his re-enactment with a pig's head had proved that point. It was hardly _his_ fault that John had been in the shower at the time. He was still unsure as to just _why_ personal privacy and hygiene were considered more important than the solving of a case.

And then there was John's reaction to the human arm suspended in jelly in the bath – but, as Sherlock had pointed out at the time, what other space in 221B was big enough to test the effects of gelatine on human decomposition?

And, yes, he was prepared to concede that having different tobacco plants growing out of a wire mesh extending across the living was a _little_ inconvenient at the time, but surely it was an over-reaction of John's to move in with his sister until they were removed?

And then there was the matter of the second bedroom. Well, it was hardly a bedroom, really – if anything, it had probably been intended to be a study.

When Sherlock had moved in and had quickly snagged the best bedroom (having already decided that the invalided-out army doctor he'd met earlier that day would be intrigued enough to share the rent), he had almost had second thoughts when he saw that spare bedroom on the third floor. Did he really _need_ a flat mate all that much? Was it worth nicking the extra rent money from Mycroft's personal bank account (pitiable security) after all? The room would have made a perfect laboratory.

Later, when John had moved in, Sherlock viewed matters differently. The second bedroom wasn't the perfect _laboratory_; it was the perfect _crime scene_. A typically sized second bedroom in a London flat, it could stand in for almost _any_ occasion when a murder victim was left in a bedroom. It helped that John added very little furniture, so the single bed and the rickety old wardrobe and chest of drawers could be moved around the big, drafty loft room with little trouble to allow Sherlock to view the crime scene again and work out the positions of the victims and their murderers.

The only real difficulty was John's old military chest. It had belonged to his grandfather, and he kept various sentimental objects in it. Sherlock hadn't troubled to pick the lock to find out exactly what – he would have been able to deduce without looking if he'd put his mind to it – but it was irritatingly large and cumbersome. More than once, he'd forgotten it was there and had tripped over it. If it grew too annoying, he would push it out into the corridor outside John's bedroom and leave it there.

For some reason, John seemed to get annoyed if Sherlock hadn't got around to moving the furniture back to its usual position before he came in from work – and he was even more irate if the chest had been moved. He didn't seem particularly interested in Sherlock's explanations about re-enactments and causes of death – which was unusual, because the doctor was usually quite receptive to his flat mate's deductions. On more than one occasion, Sherlock had found himself bundled out of the door, with muttered complaints about 'boundaries' and 'rights'.

It was a shame, really. If John was prepared to be more sensible about the matter, Sherlock would be able to extend his experiments.

For example, that _bed_. An old, open coil mattress with some suspicious damp patches on the surface and a large hole, covered by the doctor's fastidiously clean but worn, cheap sheets. So different from Sherlock's own, expensive, double bed with memory foam (present from Mycroft) and Egyptian high-count-cotton bed linen (present from Mummy), and yet, so utterly _typical_ of the usual domestic crime scene. He would _love_ to be able to test some of his theories out on it – for example, how easy would it be for an 8 stone, 5 foot woman to drive a kitchen knife through both her father and a damp, old-fashioned mattress? And was it at all possible for an ether introduced just beneath the top layer of the mattress to induce unconsciousness in a victim?

Obviously, Sherlock wouldn't test anything that was _too_ toxic. And, after all, as he pointed out helpfully, it wasn't as if John spent much time in his bedroom. Between his long shifts at the surgery and nights spent solving crimes, the doctor was hardly ever there. Surely the occasional experiment wouldn't cause too much disruption? For some reason, this rational argument had seemed to annoy John even more.

He stretched his long legs out in the back of the black cab and sighed in satisfaction. He hadn't meant to be so late tonight, but he'd had a definite breakthrough in his experiments on his latest obsession.

Cheese.

It had started a few weeks' ago. He'd worked out that the mild-mannered-looking accountant had definitely been behind the cheese merchant's death when his nose detected a smear of stilton on the man's shoe. When he'd pointed this out to John and Lestrade, they'd sniffed the air in unison and given each other a "_what planet is he on now_?" look.

Irritated, he'd continued the argument when they'd returned to Baker Street. He maintained that it was impossible for anyone to miss the stench of mature blue cheese, while John argued with equal assurance that indeed it _was _possible, on the grounds that he and Greg just had. Sherlock pointed out that John just needed to train his nose to detect the odour, while John assured him that as a doctor his nose was perfectly well trained, thanks, and he didn't intend to train it further. Sherlock wondered why, as a medical expert, John was so opposed to furthering his scientific knowledge, while John wondered why they were still having this conversation and wished him "good night".

And it had occurred to Sherlock that there might _just_ be an opportunity to make use of that old mattress after all. The hole in it was just about big enough that if one were to smear a small portion of cheese in a small sachet, one could wriggle it into the hole, cover it up with the sheet and pillow and then wait and see if one's flatmate would notice.

Well, it wasn't actually toxic or harmful. And if John's nose started to detect and differentiate between different cheeses, he'd probably thank Sherlock for the useful insight in the long run.

He'd started his experiment with Stilton. After a few days, he'd moved on to Brie, and then Roquefort, followed by Munster, then Camembert, and then the promisingly named Stinking Bishop. And, each morning, he'd eye the doctor when he came down the stairs for some sign of new awareness. And yet John would just give his usual, amiable "good morning" as he strolled into the kitchen and switched the kettle on.

Eventually, unable to endure the perceptible _lack _of tension, Sherlock had asked his flatmate outright whether he'd sensed any unusual smells _anywhere_ around the flat recently. John didn't think so, although, after some prompting, he _did_ think that there might be something in the alleyway around the back of the flat – some rotting fish perhaps – and he said that he'd talk to Mrs. Hudson about it.

Yesterday morning, Sherlock had decided to go for the jugular. He'd been assured by his source in the cheese industry that Pont l'Eveque was the nuclear missile of stinky fromage, and that anyone who couldn't detect it after a day or two was probably dead rather than just nasally challenged.

Just to make certain, Sherlock had visited a French specialist cheese shop and selected a very mature portion. When he'd arrived at Bart's to smear his Pont l'Eveque into a sachet, the usually stoical Molly had absented herself for an entire afternoon. And, most annoyingly, no taxi driver would take him. He'd had to travel in the Tube, in a carriage that was surprisingly empty. Each time the door opened, commuters would rush eagerly to an unusually quiet carriage only to turn pale and back out of it again.

He smiled, smugly. It was worth it, anyway. John hadn't said anything this morning, but he had definitely been looking a little green around the gills. It was only a matter of time, and then he'd be able to explain his experiment and they could have a good laugh together about how long it had taken for John's nose to detect the source of the smell.

He yawned and stretched a little. That could wait until tomorrow, though. Contrary to popular opinion, Sherlock _did_ enjoy a good night's rest, as long as he was not in the middle of a case. His bedroom was his sanctuary. John rarely invaded – the doctor was always sensitive to his need for privacy. Good old John… That was just one of the many advantages of having him as a flatmate…

He smiled. His bed would be clean and fresh – he'd made sure of that this morning by sweet-talking Mrs. Hudson while nicking one of her fruit scones for breakfast. When he'd left for Bart's, she'd promised to change his bed - "but just this once, dear, I'm just your landlady". Mrs. Hudson was a great find. Not only did she bake the best cakes, she was excellent at making beds. She'd always dab a few drops of Yardley French Lavender linen spray on the clean sheets, which helped him to drop into a peaceful sleep.

He closed his eyes and drifted off into a lovely dream of sitting in his clean, lavender-scented bed with a glass of whisky and an interesting book on Yves Chauvin, surrounded by his beloved possessions – his books, the bust of Goethe, the various curiosities he'd collected over the years… Peaceful. Quiet. Private… Caught up in this vision, he jumped when the cabbie tapped on the divider to tell him they had arrived at 221B.

He tossed a large tip at the man and skipped up the steps, humming cheerfully. The flat was quiet and dark; John had clearly gone to bed several hours earlier. He poured a shot of whisky into a glass and strolled across the living room to the closed door of his bedroom, smiling at the peace and tranquility.

He opened the door and walked confidently across the dark bedroom to turn on his floor lamp –

"_What the hell_…?"

In the dark, he had tripped over something that definitely _shouldn't_ be there. The whisky went flying and his arms windmilled inelegantly in a frantic attempt to stay upright. Regaining his balance, he reached out for the floor lamp, only to find that it was _not_ there.

He backed up to the door and switched on the wall light.

The object on the floor turned out to be that bloody military chest. And it was not the only interloper. His eyes skimmed the room, darting from the cheap wardrobe to the tatty chest of drawers and finally to the bed…

"_What the_ -?"

The sleeping lump in his bed – _his bed_! – turned out to be John. The doctor turned over and blinked up at him.

"What? Oh, it's you."

"What - ?" Suddenly unable to speak further, Sherlock conveyed his questions through a wild, circling gesture that took in the walls, the door, the floor and John himself.

"Oh, yeah." John sat up, rubbing his eyes. "You were right about the smell, mate. Dunno what it is, but it seems to be worse upstairs. A sort-of faint smell of… bacon, I think? Mrs Hudson is getting the environmental health people in tomorrow, but I thought I'd sleep in here tonight. I didn't think you'd mind."

Sherlock conveyed his further feelings on the matter with a highly undignified squeak.

"After all," John added, casually, "it's not as if you sleep in here much. Between the experiments and the nights solving crimes, you're hardly ever here."

The look on John's face was just a little too knowing for Sherlock's liking.

"Where's my - ?" He gave another indistinct gesture.

"Oh, yeah," John yawned, lying down again. "Well, there wasn't much room for my stuff, so I moved yours upstairs. It's all there."

He gave a vague wave towards the ceiling and turned over. "Turn the light out before you go. Cheers, mate."

Sherlock stood outside the door, wondering what the hell had just happened. He gave his head a shake and walked slowly towards the stairs.

Well, it was just for one night. A vague smell of bacon, John said. That wouldn't be too bad.

John's bedroom had been transformed. All of Sherlock's furniture was arranged exactly as it had been in his own room, right down to the last detail. The dark mahogany Queen Anne wardrobe was by the window. The heavy bookcase was near the door and containing its usual collection of curios in addition to the books. Goethe peered down from his usual shelf. John had even hung his pictures in the same place, and the haphazard pile of books on his desk was exactly as he had left it. He might have even thought it was his own room were it not for two salient facts:

1. The saggy, cheap, single bed which had been nearly made up, with military precision, with his own fresh, lavender-scented sheets.

2. The overwhelming stench of something that was decidedly _not_ bacon. In fact, he would go so far as to say it was as little like bacon as possible and something more akin to smelly socks that hadn't been washed for at least a year, overladen by the aroma of rotting flowers.

One thing was quite certain – French lavender-scented linen spray did not mix well with the overwhelming odour of a mature Pont l'Eveque that had been kept at room temperature for over thirty six hours. Even after he retrieved the little package from the hole in the mattress and threw it out of the window, the atmosphere continued to linger, almost lovingly.

After some thirty minutes or so of furious wafting of air, opening of windows and doors and liberal spraying of the room with aftershave, Sherlock admitted defeat and took himself back down the stairs to his own room.

John was sitting up in bed, playing Angry Birds on his mobile and looking rather as if he had expected Sherlock to return. He looked up at his forlorn-looking, pyjama-clad flatmate.

"Oh, were you expecting to sleep in _here_? Sorry, mate, no room."

"There's plenty of room. It's a double," Sherlock pointed out.

John's only response was a snort as he continued his game. As if to emphasise his point, he wriggled his posterior luxuriantly until he was right in the middle of the bed.

Sherlock decided pleading was worth a try. "Joooohn..."

"Nah, mate. Sorry." He didn't sound even remotely sorry.

Sherlock decided to move right along to threats. "It's _my_ bed anyway. I don't see how you could stop me if I wanted to share it."

"Oh, _don't you_?" John shifted a little, his voice deceptively light. "You want to try that and see how well it goes for you?"

Sherlock glanced at the doctor's friendly smile and then at his rippling biceps and clenched fists, and decided not to try his luck. The bruises from his last skirmish were only just fading.

He retreated from the room again, attempting to look dignified about it. As he started to ascend the stairs, he was _positive_ that he heard the very faintest of sniggers behind him.

For the rest of the night, between fresh attempts to remove the smell and some restless tossing and turning, Sherlock had very little sleep. Around dawn, he was just drifting off into a light, uneasy doze when the thought struck him… How the _hell_ had John moved the furniture all by himself?

He sat upright and switched on his lamp. He stared around John's room at the (very heavy) Queen Anne wardrobe and the (cumbersome, awkward) bookcase and all his pictures and ornaments. And finally, he stared at that haphazard pile of books on his desk, so perfectly arranged, even with that chemistry book open at the correct page...

And then he threw a pillow at it.

"_Bloody Mycroft_!"


End file.
